This invention relates to a radio channel control system of a mobile radio telephone system.
Communication with motor cars, ships, trains or other vehicles by utilizing existing telephone network systems is increasing, and various types of mobile radio telephone systems have been developed to fulfil such communication requirements. In these systems the service area is divided into a plurality of radio zones, a mobile base station (MBS) is installed in each radio zone, each base station is connected to a control unit (MCU) through a common control channel and a speech channel. The communication is transferred to an ordinary telephone network from the control unit. The purpose of utilizing the common control channel is to increase the control efficiency thereby utilizing the speech channel at high efficiencies by commonly controlling a plurality of speech channels at high speeds where mobile communication services of a high capacity and over a wide area are contemplated. However, in the prior art since the control unit has only a single controller for controlling the channel switches and the radio channels there are various problems as presented below.
In the prior art, since the control of a subscribers memory device, the control of a speech channel memory device and the control of the radio service area, are made by a single controller, the process sequence of the controller is complicated thus requiring troublesome radio link design. Furthermore, when a radio channel system device and an exchange system device are controlled by a single controller, upon occurrence of a fault, determination of whether the fault is a radio system device fault or an exchange system device fault can be made only by extremely complicated which is time consuming. With a single controller, it becomes necessary to change the radio service area when the number of the motor car telephone subscribers increases, or when the construction of highways or buildings affects radio transmission. In order to change the radio service area, not only the radio system devices but also the exchange system device of the control unit must be changed. Therefore when the exchange system device and the radio system device are as in the prior art, by a single controller there are various problems as described above and the system lacks versatility.